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3 years ago

6

A person sitting in a chair with wheels stands up, causing the chair to roll backward across the floor. How would you describe t

he momentum of the chair?

1 answer:

OleMash [197]3 years ago

3 0

Scenes the chair wheels are up the person is rolling backwards and if the wheels were down then the person would go forwards
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. A toy rocket has a mass of 350 g at launch. The force it produces

nydimaria [60]

Answer:

the acceleration is reduced by gravity

a = (15 / .35) - [9.8 * sin(65º)]

Explanation:

break the launch vector into two components, vertical and horizontal

Force Net Vertical=-9.8*.350+15cos65 N

force net horizonal=15sin65

initial acceleration= force/mass= (-9.8+15/.350*cos65)j+(15/.350*sin65)i

using i,j vectors..

5 0

3 years ago

Suppose that you make a series RC circuit with a capacitor and a known resistor that has a 5% tolerance: R= 5.20 ± 0.26kΩ. You p

Masja [62]

Answer:

correct answer is C

Explanation:

The time constant of an RC circuit is

τ = RC

so to find the capacitance

C = τ/ R

C = 2.150 / 5.20 10³

C = 4.13 10⁻⁴ F

to find the error we use the worst case

ΔC = | $|\frac{dC}{d \tau }| \ \Delta \tau + | \frac{dC}{dR} | \ \Delta R$

the absolute value guarantees that we find the worst case, we evaluate the derivatives

ΔC = 1 /R Δτ + τ/R² ΔR

the absolute values of the errors are

Δτ = 0.002 s

ΔR = 0.3 kΩ

we substitute

ΔC = 0.002 /5.20 10³ + 2.150/(5.20 10³)² 0.3 10³

ΔC = 3.8 10⁻⁷ + 1.74 10⁻⁵

ΔC = 1.77 10⁻⁵ F

the uncertainty or error must be expressed with a significant figure

ΔC = 2 10⁻⁵ F

the percentage error is

Er% = $\frac{\Delta C}{C} \ 100$

Er% = $\frac{2 \ 10^{-5} }{ 4.13 \ 10^{-4} } \ 100$

Er% = 4.8%

the correct answer is C

3 0

3 years ago

A bus can travel 63 miles in 1.4 hours. If its speed is increased

Evgesh-ka [11]

Answer:

200

Explanation:

8 0

3 years ago

A spring (k = 802 N/m) is hanging from the ceiling of an elevator, and a 5.0-kg object is attached to the lower end. By how much

love history [14]

Answer:

0.00256 m

Explanation:

For this case, we should use the Hook Law for a spring:

F= -Kx , the negative sign indicates that the force that tries to “restore” the original status of the spring, and is against the force that causes the spring´s displacement

This is, the force F required to stretch an elastic object (for example, a metal spring), is directly proportional the extension “x” of the spring

“x” can be the extension or compression of the spring, and “K” is a constant (in units of N/m)

We also know that, according to Newton´s Law:

F=m*a

m= mass

a= acceleration

Then:

m*a= -Kx

Finally, the spring has an original length of L₀, so:

- If the spring is compressed, the final strength will be: L = L₀ – x

- If the spring is extended, the final strength will be: L = L₀ + x

According to the statement:

K = 802 N/m

a = 0.41 m/s2

m = 5 Kg

Then:

x =- (m*a)/K = (5x0.41)/802 = 0.00256 m (we do not consider the negative sign, due to above explanation: it only indicates that the restoration force is always against the force imposed on the spring )

So, if the spring has an original length of L₀, when the elevator is accelerating upwards, the spring will stretch from L₀ to (L₀ – 0.00256) m

6 0

3 years ago

At sea level, liquid water changes into water vapor ata temperature of 100°C. However, at high altitudes, it changes at a

Law Incorporation [45]

The answer is A: precipitation :)

3 0

3 years ago